Improvement of PCR Targeting 16S Ribosomal DNA of Piscirickettsia salmonis

Detection of Piscirickettsia salmonis by the PCR targeting 16S rDNA has been applied to the diagnosis for piscirickettsiosis. However, some nucleotide substitutions were observed in the primer regions of the published PCR among several strains of P. salmonis. Thus, we designed a new PCR primer set targeting the 16S rDNA regions and a modified PCR program. The predicted amplicon was specifically generated from P. salmonis but not from 19 other bacterial species. Sensitivity of the present PCR system was also improved. It was confirmed that P. salmonis was detectable in the kidney and liver of the experimentally infected coho salmon Oncorhynchus kisutch by the present system.